debian/rules:  Fix tcmalloc breakage

Since all currently supported platforms have tcmalloc
available and it is now the default, remove broken check code
that turns it off if the package is not listed in build-depends.

Signed-off-by: Gary Lowell  <gary.lowell@inktank.com>
ceph.spec.in:  remove conditional checks on tcmalloc

tcmalloc is available on all supported platforms now.

Signed-off-by: Gary Lowell  <gary.lowell@inktank.com>